Coil spring



FIG. 1 is a perspective view of a coil spring, showing our new design;

FIG. 2 is an enlarged fragmentary view, showing the top portion of thecoil spring;

FIG. 3 is an enlarged fragmentary view, showing the middle portion ofthe coil spring; and,

FIG. 4 is an enlarged fragmentary view, showing the bottom portion ofthe coil spring.

The ornamental design for a coil spring, as shown and described.